Certain foods can induce a state of horror in nutritionists. Even the mere thought of them coming within a whisker of your lips will create panic, if not a stern "don't you know how bad that is for you?"

While a nutritionist's reaction may seem extreme, the fact is that these are not "real" foods. They have been subjected to excessive modern processing and are full of man-made ingredients, rendering them so unrecognisable from their original form that your body simply doesn't know what to do with them. Regularly eating these foods creates a toxic build-up that wreaks havoc on your health, as an impressive body of scientific studies show.

Truth be told, there are foods that, for the sake of health and longevity, we should not be eating at all, or, at the very least, eating only rarely. As our consumption of these foods has increased over the years, so have the incidences of obesity, diabetes and heart disease, three of the most deadly diseases worldwide.

Three white devils

Among the nutrition-savvy, these are said to be the root of all evil when it comes to health. While these foods may seem relatively benign compared to the rest of the list, they are most dangerous when eaten regularly - and for many people, that is the case. They also play a large part in many heavily processed foods, meaning that if you avoid these (and start checking ingredient lists), you will quite naturally find yourself avoiding most dangerous foods. Your health and waistline will thank you.

Sugar

This is often listed as public enemy number one. It is a significant cause of obesity and diabetes, according to the American Heart Association. Sugar also puts stress on the pancreas, liver and digestive system. The nervous system is said to be compromised by up to 50 per cent every time you eat sugar.

This is bad news for your health because it makes you more susceptible to colds, flu, depression, hormonal imbalance, stress and weight gain. As recently as 2012, the American doctor Robert Lustig called for laws that restrict sugar as if it were tobacco due to its dangerous effect on our health.

It's important to remember, however, that not all sugar is equal. Natural sugars in fruits and honey are fine when eaten in moderation.

Flour

It may seem relatively harmless but, inside your body, white flour behaves in much the same way as white sugar, since that is what it is quickly turned into during the digestive process. It puts huge stress on the pancreas and disrupts insulin levels so much that the body is sent into fat-storage mode.

Processing removes the most nutritious part of wheat, as well as most of the fibre. It's the processing that's the problem, not the grain, so again, avoid the white stuff.

Milk

This one is controversial. We are encouraged to drink milk for stronger bones but, according to the nutritionist and author Patrick Holford, we lose the ability to digest lactose, a major component of milk, as we age. Disrupted digestion causes bloating, food intolerances, makes our bodies more acidic and provokes an inflammatory response.

Most disturbing is the way milk is treated with heat, hormones, chemicals, preservatives and antibiotics. Make an easy (albeit more expensive) switch to almond, coconut or rice milk for more nutritious, easy-to-digest alternatives.

Fast food

The fastest thing about fast food is the deterioration of your health. It is full of at least two of the three white devils, not to mention highly processed meat, sodium and of course saturated fats. This is a deadly combination and one that will reduce your life expectancy.

Remember the documentary Super Size Me? Eating fast food every day for every meal is an extreme case, but, in less than a month, the researcher's health deteriorated so rapidly that his doctors were seriously concerned for his well-being.

Processed meatDeli meats are exceptionally high in nitrates and sodium, which are incredibly harmful to our health. According to the American Institute for Cancer Research, consumption of these meats is related to an increased risk of colon cancer. Nitrates are converted into nitrites once digested, which can form nitrosamine, a powerful cancer-causing chemical.DoughnutsDoughnuts contain some of the unhealthiest ingredients around: white sugar, white flour and trans-fat. This is a lethal combination, not just for your waistline, but also for your heart health. Consumption of trans-fat and sugar has been linked with a significantly higher risk of heart disease and diabetes.Potato crispsWhen foods are fried at high temperatures they can form acrylamide, which is a known carcinogen. Dale Hattis, a research professor at Clark University in Massachusetts, estimates that "acrylamide causes several thousand cancers per year in America". Not only are crisps high in fat, but they also are often coated with salt, making them extremely high in sodium. This raises blood pressure and cholesterol and, ultimately, increases your risk of heart attack and stroke.A study published inCancer Sciencein 2005 linked a high-salt diet with increased gastric cancer.Sodas (and diet sodas)A big nutrition no-no, these drinks contain absolutely no nutrients that feed your body. Worse, they fill your system with chemicals and sugar that deplete your body of nutrients. A study published inCancer Epidemiology, Biomarkers and Preventionstated that drinking just two sodas per week can nearly double a person's risk of pancreatic cancer.Dr Joseph Mercola, an American doctor and aNew York Timesbestselling author, says there are "10 teaspoons of sugar" in just one can of soda and "30 to 55 mg of caffeine, artificial food colours and sulphites".Soda also creates acid in the body, which ultimately weakens bones and depletes vital mineral stores. Studies have shown strong associations between diet soda and obesity as well as diabetes. It has been suggested that diet sodas trick the brain into thinking the body is getting sugar, affecting metabolism and prompting cravings for more sugar.MargarineMargarine is processed fat, often containing very unhealthy trans-fats, which your body cannot process. This raises your cholesterol and damages the walls of blood vessels. Whenever we eat foods that are not natural, they become a toxic burden on our system, putting immense stress on the liver. According to the Natural Health Hub, you are much better off avoiding the fake butter margarines and enjoying a little of the real thing.Canned soupsCanned foods are a stockpile of salt. Often considered a "healthy" food choice, some cans of soup can contain as much as 890 milligrams of sodium, which is nearly your full day's quota.In excess, sodium causes the body to retain water, which puts tremendous stress on the body, especially your heart, causing high blood pressure and increased risk of heart attack.According to the American Heart Association, 97 per cent of American children consume too much sodium that can lead to organ damage.That is not including the Bisphenol A (BPA) in most cans' plastic linings. An industrial chemical, BPA can leach from the linings into the food inside. Studies have shown BPA to act as an endocrine disrupter that can mimic oestrogen and cause a variety of health problems. In 2010, Canada became the first country to declare BPA a toxic substance.artslife@thenational.ae